Across the U.S., 68% of all AIDS cases occur in gay/bisexual males; in cities like San Francisco or Pittsburgh, more than 80% of those with AIDS are gay. Within the gay community, unprotected or unsafe or "risky" sexual practices remain the primary means of transmitting the HIV virus that causes AIDS. Although educational programs have made most gay men aware of "safer" sexual practices, unsafe sex continues. Because alcohol and drug intoxication impairs judgment, and because of the apparently elevated rate of alcohol and drug problems in the gay community, it has been speculated that alcohol use produces a disinhibition that leads to sexual risk taking. In fact, strong associations between drinking and unprotected sex have been demonstrated in previous correlational studies. If a causal relationship exists between substance use and risky sexual practices, then interventions focused on reducing alcohol and drug use should produce reductions in the number of unsafe sex acts. The proposed study compares no formal treatment with two different interventions. One intervention focuses on HIV risk reduction, using didactic and skill building techniques. The other focuses on HIV risk plus substance use reduction, using many of the same skill building techniques, as well as techniques borrowed from moderation drinking programs. Approximately 420 gay and bisexual males who are moderate to heavy social drinkers will be recruited from the community. They will be randomly assigned to treatment or no treatment programs, and will be followed over a one year period. During follow-up, half the intervention subjects will receive a monthly booster session, while the remainder have no booster sessions. Our hypothesis is that the booster will serve to maintain gains made during the initial intervention. Two similar studies, one in the white community (N=300) and one in the black community (N=120), will be conducted simultaneously over a four year period. Detailed weekly records about alcohol/drug use and sexual practices will be maintained; the primary outcome measures are changes in amount of alcohol consumed and in the number of risky sex acts. A major goal is to test the hypothesis that changes in drinking and drug use will produce a significant reduction in the occurrence of risky sexual practices.